No conversion to Linq Expression with MethodRef or StaticRef

[NN---]

This code leads to problem:

using System;
using System.Linq.Expressions;

class Program
{
  public static F(_ : Expression[Func[int, void -> string]]) : void
  {
  }

  static X() : string { "" }
  Y() : string { "" }

  static Main() : void
  {
    F(a => X);
    F(a => Program().Y);
  }
}

---------------------------
Assertion Failed: Abort=Quit, Retry=Debug, Ignore=Continue
---------------------------
fail convertion to 'expression tree'



   at Nemerle.Linq.Converter.ToExpr(Map`2 lparms, TExpr texpr)

   at Nemerle.Linq.Converter.TryAddConvertion(Map`2 lparms, TypeVar requiredType, TExpr nestedExpr)

   at Nemerle.Linq.Converter.ToExpr(Map`2 lparms, TExpr texpr)

   at Nemerle.Linq.Converter.ConvertLambdaExpression(Map`2 lparms, TFunHeader header)

   at Nemerle.Linq.Converter.ToExpr(Map`2 lparms, TExpr texpr)

   at Nemerle.Linq.Converter..ctor(Typer typer, TExpr tExpr)

   at Nemerle.Linq.LinqExprConvertion._N__N_lambda__14481__14566.apply(PExpr pExpr, TExpr tExpr)

   at Nemerle.Compiler.Typer.TransformWhenAllTypesWouldBeInfered(Function`3 transform, TExpr tExpr, PExpr expr)

   at Nemerle.Linq.LinqExprConvertion.ToExpressionImpl(Typer typer, PExpr expr)

   at Nemerle.Linq.ToExpressionMacro.Run(Typer _N__1, list`1 parms)

   at Nemerle.Compiler.MacroRegistry.expand_one_macro(Typer ctx, PExpr expr)

   at Nemerle.Compiler.Typer.TypeExpr(PExpr expr, TypeVar expected, Boolean is_toplevel_in_seq)

   ......

<truncated>
---------------------------
Abort   Retry   Ignore   
---------------------------

While the same code compiles in C#

using System;
using System.Linq.Expressions;

class Program
{
  public static void F(Expression<Func<int, Func<string>>> x)
  {
  }

  static string X() { return ""; }
  string Y() { return ""; }

  static void Main()
  {
    F(a => X);
    F(a => Program().Y);
  }
}

Changing void -> string to Func[string] doesn't help:

  public static F(_ : Expression[Func[int, Func[string]]]) : void
  {
  }

error : in argument #1 (_N_wildcard_3658), needed a System.Linq.Expressions.Expression[System.Func[int, System.Func[string]]], got ? -> void -> string-: ? -> void -> string- is not a subtype of System.Linq.Expressions.Expression[System.Func[int, System.Func[string]]] [simple require]
error : in argument #1 (_N_wildcard_3658), needed a System.Linq.Expressions.Expression[System.Func[int, System.Func[string]]], got ? -> void -> string-: ? -> void -> string- is not a subtype of System.Linq.Expressions.Expression[System.Func[int, System.Func[string]]] [simple require]